This invention relates to a rubber composition for use in solid golf balls.
Solid golf balls are well known as including one-, two-, and three-piece golf balls. Most solid golf balls are formed of rubber compositions. Typical rubber compositions used in the forming of solid golf balls are comprised of polybutadienes which are synthesized using nickel or cobalt base catalysts and have at least 40% of cis-1,4 bonds and a Mooney viscosity ML.sub.1+4 (100.degree. C.) of up to 60 because of their milling characteristics and processability on an extruder.
It is also known that polybutadienes synthesized using lanthanide rare earth element base catalysts would find a potential use as a rubber component of solid golf ball-forming rubber compositions.
The former polybutadienes synthesized using nickel or cobalt base catalysts and having at least 40% of cis-1,4 bond and a Mooney viscosity of up to 60 provide satisfactory workability, but leave great room for improvement in resilience property. The latter polybutadienes synthesized using lanthanide rare earth element base catalysts have never been used in commercial products because of many problems in actual applications.